68 air conditioning help

[denny]

Hi all,
Just had my original air conditioning system "restored" using R12. Drove 5miles in 80+ temps and radiator boiled over. Have not had an over-heating problem. Could it be something mechanic did wrong or should I just replace thermostat and radiator cap? Not happy after spending a GRAND+.
Thanks Denny

 

[6880 Mike]

Is the system fully charged? Take it back to the shop and have them check it.

If the thermostat is sticking closed, the AC is not the cause of the over heating.

 

[Vettehead Mikey]

Probably your mechanic inadvertently overfilled the rad or expansion tank. Many have never seen a system without a coolant recovery tank before and think they're supposed to be filled to the brim. .

Verify the coolant level and take it out for a drive. It may puke once or twice more and then behave itself having found it's own happy level.

 

[navy2kcoupe]

Another question would be "what was the water temp gauge doing while all of this was happening.
Andy Anderson

 

[denny]

The freon was completely filled . The temp kept rising till hit over 210. When shut off engine temp went over 210 close to red line and it boiled over into overflow tube. Drove it this am and all is fine. Will put in new thermostat and try in heat of day. Mechanic says nothing he did could cause problem. My question is "is he being truthfull "?

 

[SVO]

If all your mechanic did was re-charge the A/C system, then he's probably being honest with you. Depending on the condition of your cooling system, it could be on the marginal side and the heat load from the A/C sent it over the edge.

 

[krscholz]

Me too!

Brother its hot in here! I just recharged mine and the engine was running hot for me too for the first time. I believe that its just the nature of the beast.

 

[denny]

I did replace thermostat . Has not boiled over but is running about 220 in town. Stays around 210 if able to go faster and not stop at stop signs and red lights. Can always borrow wife's car on 100plus degree days. Thanks for the replies.

 

[Vettehead Mikey]

The freon was completely filled . The temp kept rising till hit over 210. When shut off engine temp went over 210 close to red line and it boiled over into overflow tube.

That's normal- running at 210+ on a hot day with AC on while stopped in traffic wouldn't even make me look twice. After the engine is shut down the coolant will continue to increase in temperature as it absorbs the residual heat from the block. If the ignition is 'on' the gauge will reflect this increase.

If the rad is overfilled or the rad cap is weak, the system will puke coolant until the pressure reduces below the cap setting.

 

[BankOfHell]

Make sure your fan clutch is the correct one for an a/c equipped car.

 

[denny]

I'm glad to hear my events are normal. Now maybe I'll watch the road instead of temp gauge THANKS!